Stay-in-place concrete form

ABSTRACT

A stay-in-place concrete form includes masonry shells layered with lightweight concrete and rigid insulation tied with plastic ladders. The masonry shells can be capped with plastic shims that compensate for the variation in height of the shells. This allows for the shells, together with the shims, to be a consistent height and allows for dry stacking. The masonry shells are bonded together with a layer of lightweight concrete poured in a cavity behind the masonry shells instead of being bonded together by mortar joints. This dry stacking method can result in labor time and training savings over conventional masonry mortar construction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of U.S. provisional application No. 61/625,447, filed Apr. 17, 2012, the contents of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to concrete forms and, more particularly, to a stay-in-place concrete form including masonry shells layered with lightweight concrete and rigid insulation tied with plastic ladders.

Formed concrete walls do not have a desirable appearance and require additional steps to insulate and finish when used as a structural wall in buildings.

Blocks mortared in place require skilled laborers with extensive training. Mortared blocks must come assembled and therefore must be lifted over reinforcement or other vertical obstacles that are required to be embedded in concrete wall construction.

Dry stacking the shells could save labor, time and training. However, masonry block is manufactured in a process that results in variations in the height of the block of plus or minus about ⅛ inch. This makes it unfeasible to dry stack masonry as the wall would not stay straight and plumb due to the variations of heights in the blocks.

Conventional stay-in-place masonry forms come in the form of blocks that needed to be mortared into place, the same as normal masonry construction.

As can be seen, there is a need for an improved stay-in-place concrete form that can be assembled around obstacles, can be dry stacked with consistent heights, and can provide insulation within the wall construction.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a stay-in-place concrete wall system comprises a masonry shell forming an exterior of a concrete wall; masonry shell channels formed along a height of the masonry shell, the masonry shell channels spaced apart by a spacing; a concrete shell forming an interior of the concrete wall; concrete shell channels formed along a height of the concrete shell, the concrete shell channels spaced apart by the spacing; a form tie ladder having a first protrusion on a first end of the form tie ladder and a second protrusion on a second, opposite end of the form tie ladder, the first protrusion operable to fit into the masonry shell channels and the second protrusion operable to fit into the concrete shell channels; and first and second rigid insulation form liners operable to disposed on each end of the form tie ladder with a space formed between the rigid insulation form liners and the masonry shell and the concrete shell, the space adapted to receive lightweight concrete.

In another aspect of the present invention, a method for forming a stay-in-place concrete wall system comprises disposing form tie ladder where a concrete wall is desired, the form tie ladder having a first protrusion on a first end of the form tie ladder and a second protrusion on a second, opposite end of the form tie ladder; sliding a masonry shell onto an exterior side of the form tie ladder, the masonry shell having masonry shell channels formed along a height of the masonry shell, the masonry shell channels spaced apart by a spacing and adapted to receive the first protrusion; sliding a concrete shell onto an interior side of the form tie ladder, the concrete shell having concrete shell channels formed along a height of the concrete shell, the concrete shell channels spaced apart by the spacing and adapted to receive the second protrusion; and securing first and second rigid insulation form liners on each end of the form tie ladder with a space formed between the rigid insulation form liners and the masonry shell and the concrete shell, the space adapted to receive lightweight concrete.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded plan view of a concrete form according to an exemplary embodiment of the present invention;

FIG. 1B is a side sectional view of the concrete form of FIG. 1A;

FIG. 2A is a plan view of the concrete form of FIG. 1A filled with both lightweight concrete and its concrete wall;

FIG. 2B is a sectional view showing a step-wise dry-stack construction of the concrete form of the present invention;

FIG. 3A is a plan view showing plastic cap shims disposed on masonry shells to create a level dry-stack of the concrete form of the present invention;

FIG. 3B is a sectional view showing the plastic cap shims being disposed on the masonry shells of the concrete form of the present invention;

FIG. 4 is a sectional view showing assembly of the components of the concrete form of the present invention;

FIG. 5A is a plan view showing installation of the rigid insulation form liner of the concrete form of the present invention;

FIG. 5B is a sectional view of an assembled masonry form according to an exemplary embodiment of the present invention;

FIG. 5C side view of a rigid insulation form liner used in the concrete form of the present invention; and

FIG. 6 is a sectional view showing the step-wise construction of the concrete form of the present invention as the lightweight concrete insulation is added as each row is added.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Broadly, an embodiment of the present invention provides a stay-in-place concrete form including masonry shells layered with lightweight concrete and rigid insulation tied with plastic ladders. The masonry shells can be capped with plastic shims that compensate for the variation in height of the shells. This allows for the shells, together with the shims, to be a consistent height and allows for dry stacking. The masonry shells are bonded together with a layer of lightweight concrete poured in a cavity behind the masonry shells instead of being bonded together by mortar joints. This dry stacking method can result in labor time and training savings over conventional masonry mortar construction.

Conventional formed concrete walls do not have a desirable appearance and require additional steps to insulate and finish when used as a structural wall in buildings. The present invention solves this problem.

Stay-in-place forms eliminate the need to strip off temporary forms for concrete wall construction. Adding insulation to the concrete wall in a later step is not required as insulation is integrated into the stay-in-place form of the present invention. The stay-in-place form can act as an exterior and/or interior wall finish that is desirable to the end user.

Prior to the present invention, stay-in-place block forms came in the form of blocks that needed to be mortared into place, the same as normal masonry construction. The present invention eliminates the need for mortar joints, provides two layers of lightweight concrete adding to the insulation value of the assembly while also improving fire resistance, moisture resistance, and sound deadening characteristics. The present invention can be assembled in the field which allows for this assembly to be constructed around construction obstacles such as vertical rebar reinforcement in concrete and/or embedded utility piping.

With the concrete forms present invention, the masonry shells can be capped with plastic shims of various thicknesses that compensate for the variation in height of the shells. This allows for the shells with the shims together to be a consistent height and allows for dry stacking. The masonry shells are bonded together with a layer of lightweight concrete poured in a cavity behind the masonry shells instead of being bonded together by mortar joints. This dry stacking design of the present invention can result in labor time and training savings over conventional block mortar construction.

Concrete wall forms consist of two vertical surfaces connected by ties spaced at close intervals so that when concrete is poured between the two surfaces they are held in place by equal and opposite forces induced by the wet concrete.

Referring now to the Figures, a form tie ladder 10, typically made of plastic such as polypropylene, can act as a tie to prevent the vertical surfaces of the concrete form of the present invention from separating under the pressure of wet concrete. The form tie ladder 10 also can act as a spacer to attach and position the other components into one stay-in-place concrete form unit. The form tie ladder 10 can attach to the same item in the course below and has a height that matches a set standardized height, such as eight inches, has a spacing at the ¼ points, such as four inches, and has a set standardized width, such as 16 inches.

The form tie ladder 10 can include a dovetail channel 12 on both sides to accept attachment of interior and exterior shell items (masonry shells 20 and concrete shells 30, described below).

The form tie ladder 10 can include I-struts 14 running horizontally across the center core to accept the insertion and placement of pre-cut rigid insulation inserts 50. The I-struts 14 also act as tension ties to resist the pressure exerted when pouring the concrete core 70 against the exterior and interior walls acting as concrete forms. The exterior concrete form can include an assembly of the masonry shells 20, the lightweight concrete 60 and the rigid insulation form liner 50. The interior concrete form wall can include the concrete shells 30 or the masonry shells 20, the lightweight concrete 60 and the rigid insulation form liner 50.

The form tie ladder 10 can come in various standardized widths so the designer of the concrete core 70 can decide on the width required to meet the configuration and load resistance requirements for the intended application.

Masonry exterior shells 20 can attach to the plastic form tie ladder 10 directly through a plastic dovetail channel connector 22 to form the finished exterior outside surfaces of the stay-in-place concrete form unit. (see FIG. 4) The masonry shells 20 in combination with the rigid insulation form liner 50 can form a confined space for the lightweight concrete insulation 60 to be poured in place in small lifts matching the height of ½ of the masonry shells 20 (see FIG. 6).

The concrete interior shells 30 can attach to the plastic form tie ladder 10 directly through plastic dovetail channel connectors 32 to form the finished interior surfaces of the stay-in-place concrete form unit (see FIG. 4). The concrete shells 30 in combination with the rigid insulation form liner 50 can form a confined space for the lightweight concrete insulation 60 to be poured in place in small lifts matching the height of ½ of the concrete shells 30 (see FIG. 6).

The concrete shells 30 can be a cementitious (autoclaved aerated concrete in one iteration) shell that forms the final interior finish of the wall assembly. The concrete shells 30 can have a consistency and appearance similar to drywall. The joints can be taped and spackled to give the appearance of a finished drywall system.

Plastic cap shims 40 can snap on top of the masonry shells 20 and can be held in place (see FIG. 3) by forcing a tongue 42 of the plastic cap shims 40 into a slot 22 in the masonry shells 20. Force can be applied to the plastic cap shims 40 and the plastic cap shims 40 can be joined with the masonry shells 20 in a manner that results in a consistent height of the two components combined (see FIG. 3).

The tongue 42 can be sized slightly larger than the slot 22 in the masonry shell 20 such that force is required to insert the tongue 42 into the slot 22. Force is applied, pushing the tongue 42 into the slot 22 until the shim is positioned at the desired location, at which time the force is no longer applied.

When properly inserted, the height of the concrete masonry shell 20 plus the plastic shim 40 would exactly match a standardized dimension, such as an eight-inch height. Dry stacking of the conventional masonry would result in walls that would be out of plumb and level.

The rigid insulation form liner 50 engages I-Struts 14 formed in the plastic form tie ladder 10 at various locations (see FIG. 5). The rigid insulation form liner 50 and the masonry shells 20 form a confined space 62 for the forming of the lightweight concrete insulation and wall form 60.

The lightweight concrete insulation and wall form 50 can be poured into confined spaces 62 formed by the rigid insulation form liner 50 and the masonry shells 20 and the concrete shells 30 in lifts that match the height of ½ of the shells 20, 30 (see FIG. 6). The lightweight concrete 60 bonds to the shells 20, 30 to permanently lock the shells 20, 30 in place. The lightweight concrete 60 also cures to create the two vertical surfaces required in a concrete forms to resist the equal and opposite forces created by pouring the concrete wall 70. The lightweight concrete 60 can engage the plastic form tie ladder 10 acting as a tension member to resist the equal and opposite forces created by the concrete wall 70.

The lightweight concrete 60 bonds the layers of shells 20, 30 together from behind the shells 20, 30 instead of between the shells as is traditionally the case in masonry construction. The method of the present invention is easier than mortared joints and results in labor savings over traditional mortared joint methods.

The concrete wall 70 is a reserved space for the concrete wall designer (see FIG. 2). The designer will determine the reinforcement and compression strength and thickness of this element. Vertical reinforcing rods, such as concrete rebar, can be placed before assembling the block wall.

The elements of the present invention can be stacked similarly to masonry block construction one course at a time. However, unlike masonry block construction, the elements of the present invention create a stay-in-place concrete wall form. The concrete wall inside becomes the structural element. The stay-in-place form adds an exterior and interior finish. The lightweight concrete insulation 60 provides insulation value, fire resistance, sound deadening characteristics, and moisture resistance along with bonding to the shells 20, 30. The rigid insulation 50 provides additional insulation value to the completed assembly.

The exterior masonry shell 20 can act as the exterior finish, eliminating a step in the construction process. The assembly eliminates the need to strip and remove concrete forms as the forms stay-in-place. Masonry walls create thermal bridges and the plastic form tie ladder 10 with rigid insulation 50 reduces the thermal bridge and saves on heating and cooling costs. The rigid insulation 50 and lightweight concrete insulation 60 combined can provide the code required insulation values and eliminate another step in the construction process.

The lightweight concrete insulation 60 forms two vertical enclosed surfaces tied together by plastic form tie ladders 10 at close spacing to facilitate concrete wall construction.

In one embodiment, the plastic members can be made from polypropylene. Molds conforming to the configurations shown in the attached figures are constructed. Each plastic piece is then reproduced repeatedly using an injection molding process.

The masonry shells 20 are configured to be compatible with standard concrete masonry unit manufacturing methods. Required amounts of sand, gravel, and cement are transferred to a weigh batcher that measures the proper amounts of each material. In the block machine, the concrete is forced downward into molds. The molds consist of an outer mold box containing several mold liners. The liners determine the shape of the block. The concrete is compacted by the weight of the upper mold head coming down on the mold cavities.

The interior concrete shells 30 can be made from autoclaved aerated concrete. This product is a baked concrete product that can be produced in slab form and can be cut and routed similar to wood. Slabs of AAC are cut to configurations compatible to standard concrete masonry units. Dovetail slots as required for connection to the plastic dovetail channels are routed onto the AAC shells.

Rigid insulation 50 can be procured in precut heights and width with the desired thicknesses.

In one embodiment, the lightweight insulating concrete 60 includes Perlite concrete. Perlite concrete can be mixed in a concrete mixer. The required amounts of water, air entraining admixture and Portland cement can be placed in the mixer and can be mixed until slurry is formed. The proper quantity of perlite concrete aggregate can then he added to the slurry and all materials mixed until design wet density is reached.

The masonry shells 20 and the plastic cap shims 40 can be assembled in the plant or at the site. The plastic cap shim 40 can be driven into the masonry shell 20 to achieve a predetermined standard assembly height. The plastic cap shim 40 has a tongue 42 that fits into the top of the dovetail slot 22 in the masonry shell 20.

In warm exterior climate conditions, it might be possible to have a mass wall where high thermal mass, such as a concrete wall, is exposed to the interior of a building. The high thermal mass can absorb heat from occupants making them feel cooler.

In the present invention, there is an exterior insulation barrier and an interior insulation barrier including lightweight insulating concrete 60 and rigid insulation 50. The interior insulating barrier can have non-insulating materials substituted in warm exterior climate conditions when high thermal mass construction is desired. The interior precut rigid insulation 50 can be replaced by cement board with the same dimensions. The lightweight insulating concrete 60 can be replaced with non-insulating concrete. This would create thermal bridging from the interior to the center concrete core 70 while maintaining the thermal break from the exterior to the center concrete core 70.

The present invention would be used to form vertical concrete walls. In one embodiment, the forms would rest on continuous spread concrete footings. The mason would first position the vertical reinforcement bars required for the concrete wall to be constructed. The present invention would be laid up in courses similar to cmu block construction. In one embodiment, the course would match 8 inch heights similar to typical masonry block construction.

The first course of masonry shells and plastic form tie ladders would be joined together around the rebar and would rest in a bed of mason's mortar. The mortar would allow for adjustments in plumb and level in this first course. Future courses after the first course would be dry stacked. The bottom of the plastic form tie ladders in this first course must be trimmed as required to prevent any interference with the spread footing base.

Rigid insulation one coarse high can be inserted into the plastic form tie ladders on both sides to create the confined space for the lightweight insulating concrete. The insulating concrete is not used until the second course is in place.

In subsequent courses the first step is to snap plastic form tie ladders onto matching form tie ladders from the course below. In one embodiment the form tie ladders would be spaced at 4 inch centers. The masonry shell assemblies with the plastic cap shims already installed would be snapped onto the tabs of the plastic form tie ladders and dry stacked onto the masonry shells from the course below. This would occur on both the interior and exterior sides of the wall.

Precut rigid insulation would be slide down from the top into the form tie ladders on both sides to create a confined space for pouring the two lightweight insulating concrete layers. The lightweight insulating concrete would be mixed on site and poured into each of the confined spaces so as to fill ½ of the block height from the course below and ½ of the block height of the current course being installed. When cured this will result in the two courses of shells to be bonded together with the lightweight insulating concrete. The second half of the confined spaces of the current course will be filled when the lightweight concrete for the course above is poured.

Any horizontal rebar required for the center core concrete wall can be placed and secured before proceeding to the next course.

The above steps can be repeated, coarse by coarse, until the stay-in-place concrete form reaches the desired height.

Once the lightweight insulating concrete layer has cured, the center concrete wall can be poured in one lift up to the designed height. This process creates an insulated concrete wall with an interior and exterior hard shell finish.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

What is claimed is:
 1. A stay-in-place concrete wall system comprising: a masonry shell forming an exterior of a concrete wall; masonry shell channels formed along a height of the masonry shell, the masonry shell channels spaced apart by a spacing; a concrete shell forming an interior of the concrete wall; concrete shell channels formed along a height of the concrete shell, the concrete shell channels spaced apart by the spacing; a form tie ladder having a first protrusion on a first end of the form tie ladder and a second protrusion on a second, opposite end of the form tie ladder, the first protrusion operable to fit into the masonry shell channels and the second protrusion operable to fit into the concrete shell channels; and first and second rigid insulation form liners operable to disposed on each end of the form tie ladder with a space formed between the rigid insulation form liners and the masonry shell and the concrete shell, the space adapted to receive lightweight concrete.
 2. The stay-in-place concrete wall system of claim 1, further comprising an I-strut disposed on the form tie ladder to retain the first and second rigid insulation form liners.
 3. The stay-in-place concrete wall system of claim 1, wherein the masonry shell channels and the concrete shell channels are dovetail shaped channels.
 4. The stay-in-place concrete wall system of claim 1, further comprising a plastic cap shim adapted to fit on the masonry shell to adjust a height of the masonry shell.
 5. The stay-in-place concrete wall system of claim 1, further comprising concrete poured in a central region, between the first and second rigid insulation form liners.
 6. A method for forming a stay-in-place concrete wall system comprising: disposing form tie ladder where a concrete wall is desired, the form tie ladder having a first protrusion on a first end of the form tie ladder and a second protrusion on a second, opposite end of the form tie ladder; sliding a masonry shell onto an exterior side of the form tie ladder, the masonry shell having masonry shell channels formed along a height of the masonry shell, the masonry shell channels spaced apart by a spacing and adapted to receive the first protrusion; sliding a concrete shell onto an interior side of the form tie ladder, the concrete shell having concrete shell channels formed along a height of the concrete shell, the concrete shell channels spaced apart by the spacing and adapted to receive the second protrusion; and securing first and second rigid insulation form liners on each end of the form tie ladder with a space formed between the rigid insulation form liners and the masonry shell and the concrete shell, the space adapted to receive lightweight concrete.
 7. The method of claim 6, further comprising pouring the lightweight concrete into the space to a height approximately one-half the way up a top course during wall construction.
 8. The method of claim 6, further comprising securing the first and second rigid insulation form liners with an I-strut formed on the form tie ladder.
 9. The method of claim 6, wherein the masonry shell channels and the concrete shell channels are dovetail shaped channels.
 10. The method of claim 6, further comprising adjusting a height of the masonry shell by securing a plastic shim cap on the masonry shell.
 11. The method of claim 6, further comprising pouring concrete in a central region, between the first and second rigid insulation form liners. 